Intraoperative nociception. “If you can’t measure it, you can’t manage it”
In clinical practice, analgesia is still empirically monitored by using variation of heart rate, blood pressure, and sweating, as the result of the sympathetic activation, or movements. The challenge of monitoring analgesia in anesthetized patients is related to the interference of hypnosis and cardiovascular drugs used during general anesthesia, and to the rapid changes of the sympathetic system activation observed during surgery.